Molecular dynamics simulation of void evolution and its mechanical response in single-crystal tungsten under extreme strain rate
BAI Xiaodan, CHEN Xun, MA Yunzhu, LIU Wensheng, LIANG Chaoping
National Key Laboratory of Science and Technology for National Defense on High-Strength Structural Materials, Central South University, Changsha 410083, China
Abstract：Molecular dynamics simulation was used to investigate the void evolution in single-crystal tungsten under uniaxial compression at extreme high strain rate (108-1011 s-1), and the mechanical properties were also tested. The results show that the yield strength and Young’s modulus decrease as a function of void radius. The plastic behavior of tungsten with different radius of void shows similar feature with the increase of strain rate. At $\dot{\varepsilon }$≥5×1010 s-1, the single crystal tungsten is changed into an amorphous structure. The amorphization of tungsten with void is delayed in comparison to perfect tungsten crystal ($\dot{\varepsilon }$≥1010 s-1). At$\dot{\varepsilon }$≤1010 s-1, before amorphization, the evolution of void during deformation the synergic effect of dislocation generation and twinning. The detailed plastic behavior follows: 1) The emission of 1/2[111] dislocation loop. 2) The decomposition of 1/2[111] screw dislocation. 3) The formation of (112)$[\bar{1}\bar{1}1]$twins, 4) the collapse of void.
百晓丹, 陈逊, 马运柱, 刘文胜, 梁超平. 极端应变率下钨孔洞演化及其力学响应的分子动力学模拟[J]. 粉末冶金材料科学与工程, 2020, 25(4): 288-295.
BAI Xiaodan, CHEN Xun, MA Yunzhu, LIU Wensheng, LIANG Chaoping. Molecular dynamics simulation of void evolution and its mechanical response in single-crystal tungsten under extreme strain rate. Materials Science and Engineering of Powder Metallurgy, 2020, 25(4): 288-295.
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2020, Vol. 25 
